The keyswitch with a scissors-type supporting mechanism has been widely utilized in a computer keyboard due to its feature of compactness.
Typically, a keyboard consists of a plurality of keys most of which are formed in square shape. However, there are some keys which have a longer dimension, such as the "ENTER", "SPACE BAR", and "SHIFT" keys. These special keys are usually referred to as the multiple-width key.
Taking the multiple-width key which employs the scissors-type keyswitch as an example, it generally includes a keycap, an internal arm, an external arm, a resilient dome, a membrane switch, and a substrate. The internal and external arms are pivotally assembled to each other, and thereby the scissors-type supporting mechanism is constituted. The substrate includes a main planar surface on which a pair of receiving grooves and a bearing portion are respectively and integrally formed. The keycap has a lower surface with a pair of first retaining portions which are spaced from each other. A pair of second retaining portions, which are spaced from each other, are also formed on the lower surface of the keycap. The internal arm is provided with a first shaft at a first end which is pivotally disposed between the pair of the first retaining portions of the keycap. The internal arm is further provided with a second shaft at a second end which is slidably and rotatably received within a bearing portion of the substrate. The external arm is provided with a projected boss which is slidably and rotatably received within a corresponding receiving groove of the substrate.
The supporting mechanism is provided to support the keycap to move vertically relative to the substrate during the operation of the multiple-width keyswitch. The resilient dome, responsive to the movement of the keycap, is deformed to contact the membrane switch to turn on the keyswitch.
However, during the operation of the multiple-width keyswitch, nose induced by impact which is generated between the keycap and the substrate can not be avoided.
Accordingly, this present invention is to provide an improved multiple-width keyswitch with capability of inhibiting noise thereof induced during operation.